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SIBEC Site Index Estimates for Complex Stands in the Northern CWH and ICH Biogeoclimatic Zones
Mah, Shirley
Rationale: The term SIBEC refers to the project (EP1215) initiated in 1994 to examine the relationship between forest growth and site units in the Biogeoclimatic Ecosystem Classification (BEC) system. Research studies have reported strong relationships between site index and environmental factors such as soil moisture and nutrient regimes. SIBEC uses these relationships to assign a site index that reflects the potential productivity of a given species to a site that has been classified to BEC site series. Since estimating site index with the SIBEC model does not require suitable site trees to be on the site, the SIBEC model is ideal for old stands and complex stands. These types of stands are in abundance in the Kalum Forest District. Site index is a critical parameter in growth and yield models such as VDYP and TASS/TIPSY, the most prominent models in use in British Columbia. The SIBEC estimates of site index are used to support forest management in areas such as Timber Supply Review and strategic silviculture strategies. This single-year project will address the FIA Forest Science Program strategic goal of improving knowledge-based science in support of improving timber growth and value. SIBEC estimates are being increasingly used in forest management units in British Columbia, such as Innovative Forest Practices Agreements (IFPA) and Defined Forest Area Management (DFAM) undertaking ecologically based timber supply analyses. However, a large proportion of the SIBEC model is still based on first approximation estimates, as opposed to the improved second approximation estimates, and are reported in site index classes. SIBEC sampling has occured in the Kalum Forest District in the past. In fact, our project is a continuation of 2005-2007 SIBEC data collection efforts in the ICHvc, ICHmc1, ICHmc2, CWHvm1, CWHws1, and CWHws2 units. New SIBEC data are required to achieve second generation estimates that report mean site index and standard error (Mah and Nigh 2003; B.C. Ministry of Forests 2003). Description: The purpose of our project is to support the continued development of the SIBEC model by completing the SIBEC sampling matrix for site series in the CWH and ICH zones of the Kalum Forest District. In 2007/08, priority sampling will include approximately 85 additional plots in the CWHvm, CWHws2 and ICHmc2 subzone/variants in the Kalum Forest District. In addition to the Kalum project, it is anticipated that SIBEC data will also be collected in Mountain Pine Beetle impacted areas in the central and southern interior of British Columbia. All newly acquired SIBEC data, including the Kalum data and data from other areas, will be incorporated into the SIBEC data warehouse, analyzed and released as 2nd approximation site index estimates. The new provincial site index estimates will be released as a report, ?Site index estimates by site series: report by Biogeoclimatic unit (2008 approximation) and made available on the SIBEC website: in PDF and EXCEL formats. This report will provide forest managers with a more accurate estimate of relative tree species productivity for a greater number of BEC site series. Plots established as part of the Kalum SIBEC project will also be used in the establishment of an ecosystem recovery project in the Northern Interior Forest Region. This is an expansion of a project initiated in the Coast Forest Region by Allen Banner and others in 2004 ( Since 2005, the Kalum SIBEC sampling has contributed to the establishment of ecosystem recovery plots in three Interior Cedar Hemlock subzone/variants and three Coastal Western Hemlock subzones/variants. Literature cited B.C. Ministry of Forests. 2003. Site Index Estimates by Site Series: Report by Biogeoclimatic Unit (2003 Approximation). [electronic resource] Res. Br., Victoria, B.C. Mah, S. and G.D. Nigh. 2003. SIBEC site index estimates in support of forest management in
Report Number
Final Technical Report
Site Index Estimates

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